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%I #23 May 26 2021 09:22:56
%S 4,10,19,29,43,58,79,101,126,152,185,219,254,292,331,377,426,477,532,
%T 589,647,709,774,843,917,994,1076,1161,1247,1334,1425,1518,1612,1707,
%U 1813,1924,2039,2157,2276,2397,2519,2642,2771,2904,3038,3179,3321,3464
%N Sum of first n semiprimes.
%C Elements in this sequence can themselves be semiprimes. a(1) = 4 = 2^2. a(2) = 10 = 2 * 5. a(6) = 58 = 2 * 29. a(11) = 185 = 5 * 37. a(12) = 219 = 3 * 73. a(13) = 254 = 2 * 127. a(16) = 377 = 13 * 29. a(20) = 589 = 19 * 31. Etc. Does this happen infinitely often? - _Jonathan Vos Post_, Dec 11 2004
%H Harvey P. Dale, <a href="/A062198/b062198.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = Sum_{i=1..n} A001358(i). - _R. J. Mathar_, Sep 14 2012
%e a(4) = 29 because the sum of the first 4 semiprimes 4+6+9+10 is 29.
%t Accumulate[Select[Range[200],PrimeOmega[#]==2&]] (* _Harvey P. Dale_, Jul 23 2014 *)
%o (PARI) is_A062198(N)={ my(n=0); while(N>0, while(bigomega(n++)!=2, ); N-=n); !N} \\ - M. F. Hasler, Sep 23 2012
%o (PARI) A062198(n, list)={my(s=0, N=0); until(!n--, until(bigomega(N++)==2, ); s+=N; list & print1(s", ")); s} \\ - _M. F. Hasler_, Sep 23 2012
%Y Cf. A001358, A092189, A092190.
%K easy,nonn
%O 1,1
%A _Shyam Sunder Gupta_, Aug 24 2003
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